Valve assemblies to control the fluid level and vapor flow for fuel tanks are known. Fuel tanks used with small engines commonly work on a gravity feed system to transmit the fuel to the engine. With gravity feed systems, maintaining some pressure within the fuel tank is desirable. However, gravity feed systems will not operate under vacuum conditions. Thus, the valve assemblies must be able to vent vapor within the fuel tank and maintain the pressure level within the fuel tank. As is known, the vapor is typically vented into the intake line for the engine. Additionally, these valve assemblies will also vent vapor to maintain pressure within the fuel tank as a result of changes in the fuel level.
Rollover valves are installed in the fuel tanks to prevent the liquid from reaching the valve assemblies. However, the rollover valves are open during normal operating conditions. Therefore, some liquid may still escape through the valve assemblies due to sloshing of the liquid during normal fuel tank usage.